HIGH INERTIA ROTOR FOR A DYNAMOELECTRIC MACHINE

摘要

CASE - 2580 This invention relates to a high inertia rotor for use in a dynamoelectric machine. The inertia of the rotor is increased over that of standard rotors by providing a plurality of inertia packets secured to the shaft adjacent the ends of magnetic core and the rotor winding. The inertia packets are enclosed within the stator of the machine. The added inertia supplied to the rotor from the packets prevents a rapid decrease in rotor speed upon interruption of electrical supply to the machine. Each inertia packet is comprised of unifrom non-magnetic discs of metallic sheet material having minimal electro-magnetic losses. In the event of rotor failure leading to the fracture of a disc, some disc fragments would be propelled into the stator winding, resulting in the creation of an electrical fault condition, whereby the motor would trip out before additional damage could occur. This rotor is particularly suited for use as a pump motor in a nuclear reactor. Previous practice in providing additional inertia has been to use a solidly forged flywheel mounted outside the stator winding. Such flywheels due to their location and concentrated mass, necessiatated the provision of shielding about them to contain fragments from a fractured flywheel which could otherwise become projectiles in the environment surrounding the flywheel. The present invention eliminates the need for such a prior art flywheel, with its associated shielding, while reducing the overall size of the high inertia machine.